title: Desensitization of human CRF2(a) receptor signaling governed by agonist potency and βarrestin2 recruitment.
abstract: The primary goal was to determine agonist-specific regulation of CRF2(a) receptor function. Exposure of human retinoblastoma Y79 cells to selective (UCN2, UCN3 or stresscopins) and non-selective (UCN1 or sauvagine) agonists prominently desensitized CRF2(a) receptors in a rapid, concentration-dependent manner. A considerably slower rate and smaller magnitude of desensitization developed in response to the weak agonist CRF. CRF1 receptor desensitization stimulated by CRF, cortagine or stressin1-A had no effect on CRF2(a) receptor cyclic AMP signaling. Conversely, desensitization of CRF2(a) receptors by UCN2 or UCN3 did not cross-desensitize Gs-coupled CRF1 receptor signaling. In transfected HEK293 cells, activation of CRF2(a) receptors by UCN2, UCN3 or CRF resulted in receptor phosphorylation and internalization proportional to agonist potency. Neither protein kinase A nor casein kinases mediated CRF2(a) receptor phosphorylation or desensitization. Exposure of HEK293 or U2OS cells to UCN2 or UCN3 (100nM) produced strong βarrestin2 translocation and colocalization with membrane CRF2(a) receptors while CRF (1μM) generated only weak βarrestin2 recruitment. βarrestin2 did not internalize with the receptor, however, indicating that transient CRF2(a) receptor-arrestin complexes dissociate at or near the cell membrane. Since deletion of the βarrestin2 gene upregulated Gs-coupled CRF2(a) receptor signaling in MEF cells, a βarrestin2 mechanism restrains Gs-coupled CRF2(a) receptor signaling activated by urocortins. We further conclude that the rate and extent of homologous CRF2(a) receptor desensitization are governed by agonist-specific mechanisms affecting GRK phosphorylation, βarrestin2 recruitment, and internalization thereby producing unique signal transduction profiles that differentially affect the stress response.
authors.affiliation: Center of Excellence for Stress and Mental Health, San Diego VA Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA; Department of Psychiatry, School of Medicine, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA. Electronic address: rhauger@ucsd.edu.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Hauger
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Olivares-Reyes
authors.forename: Sandra
authors.initials: S
authors.lastname: Braun
authors.forename: Judith
authors.initials: J
authors.lastname: Hernandez-Aranda
authors.forename: Christine C
authors.initials: CC
authors.lastname: Hudson
authors.forename: Eric
authors.initials: E
authors.lastname: Gutknecht
authors.forename: Frank M
authors.initials: FM
authors.lastname: Dautzenberg
authors.forename: Robert H
authors.initials: RH
authors.lastname: Oakley
mesh_terms: D029845:Amphibian Proteins / Q000494:pharmacology / Q000502:physiology; D019390:Arrestins / Q000378:metabolism*; D045744:Cell Line, Tumor; D005576:Colforsin / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D036361:Peptide Hormones / Q000494:pharmacology / Q000502:physiology; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D018019:Receptors, Corticotropin-Releasing Hormone / Q000819:agonists / Q000378:metabolism*; D015290:Second Messenger Systems; D054832:Urocortins / Q000494:pharmacology / Q000502:physiology; D000071557:beta-Arrestins; D000099052:CRF Receptor, Type 1
chemical_list: D029845:Amphibian Proteins; D019390:Arrestins; C101531:CRF receptor type 2; D036361:Peptide Hormones; D018019:Receptors, Corticotropin-Releasing Hormone; C576814:UCN protein, human; C426705:UCN2 protein, human; C426704:UCN3 protein, human; D054832:Urocortins; D000071557:beta-Arrestins; D005576:Colforsin; D000099052:CRF Receptor, Type 1; C025727:sauvagine; D003346:Corticotropin-Releasing Hormone; D000242:Cyclic AMP
keywords: CK1; CK2; CRF receptor type 1; CRF receptor type 2(a); CRF(1) receptor; CRF(2(a)) receptor; Corticotropin releasing factor receptor (CRF); G protein-coupled receptor; GPCR; GPCR kinase; GRK; K44A; PKA; PKC; SCP; SRP; Urocortin 1 (UCN1); Urocortin 2 (UCN2); Urocortin 3 (UCN3); casein kinase 1; casein kinase 2; dynamin dominant negative mutant; protein kinase A; protein kinase C; stresscopin; stresscopin-related peptide; βarrestin2